The following disclosure relates generally to an apparatus, method, system, computer program, and product, each capable of extracting embedded information from a document.
Information that is not perceptible to the human eye is often embedded into a document for the purpose of establishing the ownership of the document, tracking the origin of the document, protecting the document from unauthorized alteration, checking the integrity of the document, etc. In order to achieve such purposes, the embedded information needs to be extracted with high accuracy. However, due to its imperceptible nature, extracting the embedded information often requires some effort and time.
For example, the embedded information may be embedded in the form of a dot pattern. In order to extract the dot pattern with high accuracy, various forms of image processing are often applied to specify the location of the dot pattern. In one example, a filter capable of detecting the dot pattern may be applied to the document. In another example, additional information indicating the location of the dot pattern may be previously embedded in the document in a corresponding manner with the dot pattern.